Heat saving device for furnaces



Oct. 2l, 1958 A. HQBARTELS 2,856,992

HEAT sAvING DEVICE FOR FURNACES v Filed Feb. 2s, 1956 United States Patent() HEAT SAVING DEVICE FOR FURNACES Albert H. Bartels, Pierre, S. Dak., assignor of one-half to Leo 'I'. Schmit, Pierre, S. Dak.

Application February 23, 1956, Serial No. 567,145

3 Claims. (Cl. 158--28) This invention relates to heat saving devices. More particularly it relates to automatically actuated dampers for use in conjunction with furnaces requiring considerable air ow therethrough such as is the case in oil burning furnaces.

All oil burning furnaces require considerable draft and the heat loss during the time the furnace is not burning is estimated at approximately 35%. This heat loss is caused by the warm air passing upwardly through the stack which is connected with the furnace during the period that the furnace is not burning and the consequent replacement of this air by cool air which must be drawn from the outside. In other words, in most oil burning furnaces there is a draft regulator through which there is a steady flow of air upwardly through the stack and since this air must come from within the house or building being heated by the furnace, it is obvious that there is a substantial loss of heat through this medium. My invention is designed to eliminate this undesirable feature.

It is a general object of my invention to provide a novel and improved damper mechanism-for use in conjunction with oil burning furnaces.

A more specic object is to provide a novel and improved damper mechanism for use in conjunction with oil burning furnaces which is automatic in function and of unusually simple and inexpensive construction.

Another object is to provide automatic damper mechanism for oil burning furnaces and the like which is small in compass and simple and inexpensive to manufacture and install and inexpensive to operate.

Another object is to provide a novel automatic damper mechanism for use in conjunction with oil burning furnaces which is highly eicient in operation yet simple and inexpensive to manufacture and install.

These and other objects and advantages of my invention will more fully appear from the following description made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views, and in which:

Fig. 1 is a side elevational view of one embodiment of my invention applied to the stack of an oil burning furnace, the damper being shown in closed position.

Fig. 2 is a side elevational view of the same with portions being broken away to show the damper in open position and to show the interior of the air damping mechanism.

Fig. 3 is a vertical sectional view taken along line 3-3 of Fig. 1.

Fig. 4 is a fragmentary side elevational view taken along line 4 4 of Fig. 3.

Fig. 5 is a schematic wiring diagram illustrating the circuits utilized in conjunction with my damper mechanism.

One embodiment of my invention may include, as shown mounted on the stack 6 in Figs. l-4,` a damper 7 which is mounted within the stack for pivoting movement between closed position as shown in broken lines in Figs. 1-2 and open position as shown in solid lines in Fig. 2. The damper 7 is mounted on a pivot rod 8 which extends transversely through the stack 6 and is journalled in the side walls thereof, as best shown in Fig. 3. This pivot rod 8 extends outwardly beyond the stack 6 on opposite sides thereof, as shown in Fig. 3, and provides a pivotal mounting for the damper which, as shown in Fig. 3, is slightly less in diameter than the diameter of the stack 6.

Secured to the outer surface of the stack 6 by bolts such as 9 is a mounting bracket indicated generally as 10. This mounting bracket has a lower platform 11 and a guide plate 12 at its upper portion. As best shown in Fig. 3, the pivot rod 8 extends through this mounting bracket through a journal 13.

Mounted on the platform 11 is a solenoid 14 which is thermostatically controlled as illustrated in Fig. 5, the thermostat being indicated by the numeral 15. This thermostat is of the conventional type found in the home and need notv be further described in view of its wellknown structure by those acquainted with the art. The solenoid has a pair of upstanding ears 16 and 17 at its upper end which are carried by the armature 18 of the solenoid. Secured to these ears 16 and 17 is a guiding post or rod 19, the connection being accomplished by a pin 2l) which extends through the lower end of the rod and through both of the ears 16 and 17. This guiding rod 19 extends upwardly through the guiding plate 12 through an aperture provided therein for that purpose. The lower end portion 21 of the rod 19 is slightly larger in diameter than the rest of the rod 19, as best shown in Fig. 3.

Mounted on the guiding rod 19 in free sliding relation is a sleeve member 22 which, when at its lowest elevation, abuts against the enlarged end portion 21 of the rod 19. Secured to the top of the sleeve 22 is a cross bar 23 and secured to the opposite ends of this cross bar is a pair of coiled springs 24 and 25, each of these springs being extended and connected under tension to the pin 20, as best shown in Figs. 1 and 2.

Connected to the back side of the sleeve member 22 as best shown in Fig. 3, is a pivotpin or rivet 26 upon which is pivoted a link member 27. The opposite end of the link 27 is pivoted upon a pivot pin 28 which is mounted upon and extends forwardly from a disc member 29. The disc member 29, as best shown in Fig. 3, is ixedly secured and mounted upon the protruding end portion of the pivot rod S for rotation therewith. Thus, when the sleeve 22 moves upwardly and downwardly on the rod 19, the disc 29 will be caused to rotate about the axis of the pivot rod 8 because of the offset positioning of the pin 28. In this manner the damper 7 may be pivoted back and forth between open and closed positions.

Mounted upon the mounting plate 10 is a normally open switch 30. This switch has a pair of contacts 31 and 32 which, as shown in Fig. l, are normally spaced from each other but may be brought into engagement with each other, as shown in Fig. 2,`\through rotation of the disc 29 which will bring the switch engaging member or post 33 into engagement with the switch and force the contacts 31 and 32 into closed engaging position. This switch 30 as illustrated in Fig. 5 is interposed Within the circuit of the oil burner which is indicated bythe numeral 34 and as illustrated in Fig. 5 this switch is closed as a result of energization of the solenoid 14.

It will be noted that the switch engaging member 33 engages the switch 30 to close its contacts just as the damper 7 reaches open position, as can best be seen by reference to Fig. 2.

Secured to the opposite side of the stack 6 relative to the mounting plate 10 is a second mounting plate 35. As best seen in Fig. 3, the protruding end of the-pivot post8 Patented Oct. 21, 1958 to the mounting plate 35, the spring 36 being constantly under tension so as to tend to rotate the pivot rod 5 so as to turn the damper 7 to closed position as shown in Fig. l. The spring 36 is of the type commonly utilized as the main spring in a common alarm clock and it constantly urges the damper 7 toward closed position.

Secured to the peripheral portions of the disc 29 is a pivot post 33. Pivotally mounted on this pivot post 38 is a piston rod 39 which carries a piston 40 at its opposite end, theA piston being` free to slide within a cylinder 41 which, in turn, is pivotally mounted at its lower end upon the mounting plate 10. The lower end of the cylinder 41 is provided with an air bleeder opening 42 which is partially obstructed by an adjustable needle valve 43, the latter being adjustable so as to control the amount of air permitted to ow through the bleeder opening 42. The pivot post 38, the piston rod 39, the piston itl and the cylinder 41 together constitute a retarding mechanism or air damping mechanism which may be indicated generally as M, the function of the same being to regulate the speed with which the spring 36 returns the damper from open to closed position and to regulate the speed with which the springs 25 open the damper following operation of the solenoid armature.

In operation, the damper 7 is in closed position until the circuit of the thermostat is closed as a result of theroom temperature dropping to a low predetermined level. The closing of the circuit of the solenoid 14 by the thermostat 15 energizes the solenoid 14 and thereby causes the armature 18 to be drawn downwardly from the position shown in Fig. l to the position shown in Fig. 2. As this occurs the springs Z4 and 25 are extended, these springs acting as connector means between the armature and the disc 29. This sudden downward movement of the armature 18 causes the sleeve 22 to automatically remain in elevated position as shown in Fig. l and to be gradually drawn downwardly to the lower position shown in Fig. 2 by these spring elements. Of course, with the descent of the sleeve 22, the disc 29 is caused to pivot or rotate about the axis of the piovt rod 2B through the action of the link 27. As the disc 29 pivots the switch engaging member 33 swings toward the contacts 31 and 32 of the switch 30 and just as the damper reaches open position, as shown in Fig. 2, the switch engaging member forces the contacts 31 and 32 to enage each other and thereby complete the circuit to the oil burner 34, as is illustrated in Fig. 5. The oil burner is thereby actuated and it will continue to burn until such time as the temperature of the room reaches a predetermined level at which the thermostat is set whereupon the thermostat circuit will be broken and as a result the solenoid 14 will be de-energized.

With the de-energization of the solenoid 14 the strength of the coiled spring 36 is sucient to cause the pivot rod 3 to immediately commence to rotate about its axis and thereby turn or pivot the disc 29 back toward its original position, as shown in Fig. l. During the initial stages of this movement, the switch engaging member 33 disengages the contact 31 and permits the two contacts 31 and 32 to separate thereby interrupting the circuit to the oil burner 34. The rapid return of the damper 7 to closed position, however, is precluded by the presence of the damping mechanism M for, as the disc 29 proceeds to rotate about the axis of the pivot rod 8, the air which has been drawn in behind the piston 40 is gradually permitted to escape through the bleeder opening 42. The valve is preferably set so as to cause a delay of approximately seconds in the movement of the damper 7 from open to closed position This valve 43 may be set so as to require a period of as great as 8i) secondsV but lhave found that best results are obtained when approximately a 20 second period is permitted to elapse. At the end of this periodl the spring 36 will have caused the damper 7 to return to its closed position and thereby substantially all of the ow of hot air upwardly through the stack will be cut oit. The damping mechanism is utilized in order to assure that all of the combustion cases from the burner 34 have been permitted to escape before the damper is completely closed.

Onev of the main advantages of my heat saving device is its simplicity in construction and operation and inexpensiveness. It can be readily seen through reference to the drawings that my heat saving device is extremely simple in construction and yet entirely automatic with no possibility of malfunctioning through ignition of the burncr before the damper has reached open position. The entire device can be manufactured at a very nominal cost and yet it will function in a most desirable manner.

It will be noted also that, through the simple and novel construction disclosed herein, a slight delay is assured at the end of the burning of the oil burner before the damper is closed. This permits all of the combustion gases to flow upwardly through the stack and escape through the chimney before the damper is closed and thus precludes the possibility of entrapment of such gases within the furnace and possible seepage thereof outwardly through the house with consequent discomfiture to the occupants.

It can be readily seen that my heat saving device is entirely automatic in function. The damper automatically closes shortly after the thermostat circuit is broken and the burner is automatically cut oft shortly prior to the closing of the damper. Also, when the thermostat circuit is closed by the temperature of the room falling below the level at which the thermostat is set, the damper is automatically opened and as the damper reaches its open position the burner is automatically set in operation through the closing of the switch 3l).

Another advantage of my heat saving device is that it is so constructed as to avoid the rapid wear which would occur upon such a device if the disc 29 were connected by rigid linkage to the armature 1S of the solenoid. The consequent jarring which would result from the rapid manner in which the armature is drawn downwardly would cause this device to be relatively short-lived in the absence of the resilient connector mechanism which I utilize between the armature of the disc 29. The springs 24 and 25 eliminate this jarring tendency so that the movement of the damper from closed to open position is a smooth operationwith a minimum of jarring and damage to the mechanism.

Another advantage of my heat saving device, in addition to the fact that approximately a 35% saving is effected in the amount of fuel which is required, is that it is a very simple device to install. The device may, it desired; be connected upon a short piece of tubing of the same diameter as the stack 6 and inserted in the stack for simple installation.

It will, of course, be understood that various changes may be made in the form, details, arrangement, and proportions of the various parts without departure from the scope of my invention.

What is claimed is:

l. Ina heating saving device for use in the stack of an electrically actuated burner, a damper constructed and arrangedto be pivotally mounted within such a stack for movement between open and closed positions, pivot means connected tosaid damper and pivoting therewith, a normally open switch mounted adjacent said pivot means and adapted to be interposed within the actuating electric circuit of the burner, a switch-engaging member carried by said pivot means in spaced relation to said switch and pivoting'with said pivot means and arranged to engage and close said switch as said damper reaches open position, a thermostatically controlled solenoid having a movable elongated armature means, a slidable member supported by said armature means and slidable longitudinally with respect thereto, said slidable member being drivingly connected to said pivot means, longitudinally extending resilient tension connector means having the opposite ends thereof secured to said slidable member and said arma.- ture means respectively and urging said slidable member longitudinally toward said solenoid upon actuation of said solenoid and movement of said armature means longitudinally with respect to said slidable member, mechanical retarding means connected to said pivot means and retarding pivotal movement of said pivot means in opposite pivoting directions, and mechanism connected to said damper for returning the same to closed position when said solenoid is not actuated.

2. In a heat economizing system, an electrically actuated burner, a stack connected with said burner to conduct gases of combustion away therefrom, a damper, means pivotally mounting saiddamper within the stack for movement between open and closed positions, a normally open switch mounted adjacent said mounting means and interposed within the actuating electric circuit of the burner, a switch-engaging member mounted on said mounting means and pivoting therewith and arranged to engage said switch and close the same as said damper reaches open position, a single solenoid constituting the sole electromotive device for actuating said mounting means, said solenoid having an elongated armature means, a slidable member supported by said armature means and slidable longitudinally with respect thereto, said slidable member ibeing drivingly connected to said mounting means, longitudinally extending resilient tension connector means having the opposite ends thereof secured to said slidable member and said armature means respectively and urging said slidable member longitudinally toward said solenoid upon actuation of said solenoid and movement of said armature means longitudinally with respect t-o said slidable member, mechanical retarding means connected to said mounting means and retarding pivotal movement of said mounting means in opposite pivoting directions, resilient means connected with said mounting means and constantly urging said damper toward closed position, and a room thermostat positioned outside said stack and electrically connected in controlling relation with said solenoid whereby said solenoid will be actuated to operate said damper when the temperature around said thermostat reaches a predetermined level.

3. Apparatus as dened in claim 2 wherein said mechanical retarding means comprises air-damping mechanism pivotally connected to said mounting means.

References Cited in the file of this patent UNITED STATES PATENTS 2,053,750 Terry Sept. 8, 1936 2,117,787 Bock May 17, 1938 2,271,690 Goiredo Feb. 3, 1942 2,446,834 Kaufman Aug. 10, 1948 2,508,885 Mackay May 23, 1950 FOREIGN PATENTS 233,521 Switzerland Aug. 15, 1944 

